The recent trend is toward an increase in the amount of signal processing using a DSP, which can digitally process a sound, a musical instrument sound and an audio signal. In order to cope with this trend, DSPs having a high signal processing capacity are utilized, or a plurality of DSPs are utilized.
In order to apply an effect to a musical tone output from a sound source, such as an electronic musical instrument, a DSP for performing signal processing for effect application includes an external memory, which is used for the purpose of delay processing or the like.
It is common that such a DSP 2c is used, having an external memory 102 connected thereto for storing a digital delay data as shown in FIG. 20. This figure shows that one sampling cycle (44.1 KHz) contains sixty-four timings when the access to the external memory 102 is available.